The present invention relates to a locking mechanism and, more specifically, to a vibration-resistant lock for sliding doors or windows.
In recent years the popularity of sliding doors and windows as an architectural element for residential housing has grown rapidly. A typical sliding door is mounted in a six to ten foot wide wall space extending from floor level to door height. A outer rectangular frame is attached to surround the space, and defines tracks or other means on the upper and lower edges thereof to permit sliding of one or more inner frames resting within the outer frame.
Generally, two inner frames are mounted within the outer frame. Each frame may contain at least a single pane of glass, and at least one of the frames is permitted to slide horizontally so as to open or close the space. Each sliding frame is typically provided with some form of locking mechanism intended to secure the inner frame in a fully closed position to prevent unauthorized entry to the premises. The locking mechanism is ordinarily incorporated within a vertical portion of the sliding inner frame which rests adjacent a vertical portion of the outer frame when the door is fully closed.
A standard prior art locking mechanism comprises a latch accessed from the indoor side of the inner frame, a latch port definded in the inner frame facing the outer frame, and a locking pin attached to the latch to engage a hook attached to the outer frame and extending through the port into the locking mechanism when the door is fully closed. The pin and latch have a simple vertical motion which normally involves a very small distance between the locked and unlocked positions. Moreover, the locking mechanism includes very little friction or inertia, so that modest vibrations applied to the inner frame from any side of the door will move the latch and pin from the locked state to the unlocked state. This characteristic of the standard prior art locking mechanism has lead to a steady increase in burglary, trespassing, and other unauthorized entries in homes utilizing sliding doors or windows.
Thus, it can be seen that there is a need for a locking mechanism for sliding doors or windows which incorporates a vibration-resistant positive locking feature, and which is easy to use from inside a dwelling.